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Abstract and Figures

Microdosing psychedelics - the regular consumption of small amounts of psychedelic substances such as LSD or psilocybin - is a growing trend in popular culture. Recent studies on full-dose psychedelic psychotherapy reveal promising benefits for mental well-being, especially for depression and end-of-life anxiety. While full-dose therapies include perception-distorting properties, microdosing may provide complementary clinical benefits using lower-risk, non-hallucinogenic doses. No experimental study has evaluated psychedelic microdosing, however; this pre-registered study is the first to investigate microdosing psychedelics and mental health. Recruited from online forums, current and former microdosers scored lower on measures of dysfunctional attitudes and negative emotionality and higher on wisdom, open-mindedness, and creativity when compared to non-microdosing controls. These findings provide promising initial evidence that warrants controlled experimental research to directly test safety and clinical efficacy. As microdoses are easier to administer than full-doses, this new paradigm has the exciting potential to shape future psychedelic research.
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Microdosing Psychedelics: Personality, mental health, and creativity differences in
Thomas Anderson, Rotem Petranker*, Le-Anh Dinh-Williams, Daniel Rosenbaum, Cory
Weissman, Emma Hapke, Katrina Hui, & Norman Farb
Accepted to Psychopharmacology
*corresponding author:
Microdosing psychedelics the regular consumption of small amounts of psychedelic
substances such as LSD or psilocybin is a growing trend in popular culture. Recent studies on
full-dose psychedelic psychotherapy reveal promising benefits for mental well-being, especially
for depression and end-of-life anxiety. While full-dose therapies include perception-distorting
properties, microdosing may provide complementary clinical benefits using lower-risk, non-
hallucinogenic doses. No experimental study has evaluated psychedelic microdosing, however;
this pre-registered study is the first to investigate microdosing psychedelics and mental health.
Recruited from online forums, current and former microdosers scored lower on measures of
dysfunctional attitudes and negative emotionality and higher on wisdom, open-mindedness, and
creativity when compared to non-microdosing controls. These findings provide promising initial
evidence that warrants controlled experimental research to directly test safety and clinical
efficacy. As microdoses are easier to administer than full-doses, this new paradigm has the
exciting potential to shape future psychedelic research.
1. Introduction
Microdosing psychedelics the practice of regularly consuming very low doses of
psychedelic substances such as lysergic acid diethylamide (LSD) or psilocybin (“magic”
mushrooms) is a growing practice despite a lack of scientific research validating its effects.
One online microdosing forum (/r/microdosing subreddit, Reddit Inc, San Francisco, CA, USA)
has almost 40,000 subscribers and doubled its subscriber count in the past year (Figure 1). The
popular media has described consumption of psychedelics in doses much lower than typical
therapeutic doses (Fadiman, 2011; Leonard, 2015; Solon, 2016; Waldman, 2017) and articles and
anecdotes claim benefits including improved mood, focus, and creativity alongside decreased
symptoms of depression and anxiety. While decreased depression and anxiety are consistent with
research on full-dose psychedelics (Carhart-Harris et al., 2017; Griffiths et al., 2016),
microdosing could offer these benefits without any perceptual distortions and reduced need for
expensive clinical oversight typical of full-dose psychedelic psychotherapy. Nevertheless, both
LSD and psilocybin are controlled substances in most countries and so members of the public
enticed by purported benefits of microdosing expose themselves to the risks implied by
criminalized activity. For example, in the US, LSD and psilocybin are schedule I controlled
substances, meaning that they have no accepted therapeutic use. Such risks are exacerbated by an
absence of even minimal scientific evidence that normally surrounds clinical use, such as data on
safety, efficacy, common side-effects, contraindications, and appropriate dose and dose schedule.
Figure 1. Rise in subscribers to an online microdosing forum, As of
October 2018, the subscriber count has reached nearly 40,000 subscribers, doubling in less than
one year.
It is unlikely that normative standards for microdosing will emerge without an initial
description of current microdosing practices and associated outcomes. We therefore measured
self-reported practices and psychological function of participants in existing microdosing
communities and compared them to control participants with no microdosing experience. This
design allows for a structured description of the common practices used in microdosing from
which future clinical trials can build.
1.1 Full-dose Psychedelics
Interest in microdosing is likely predicated on research linking clinical benefits to full-
dose psychedelic use. By 1975, over one thousand studies had linked psychedelic substance use
with salutary effects on mental health and personal growth (Greenspoon & Bakalar, 1979). More
recent research suggests efficacy for a number of health conditions, including obsessive
compulsive disorder (Moreno et al., 2006), alcohol dependence (Bogenschutz et al., 2015),
tobacco dependence (Johnson et al., 2014), depression (Carhart-Harris et al., 2017; Osório et al.,
2015), and end-of-life anxiety (Griffiths et al., 2016; Ross et al., 2016).
While research on psychedelics provides evidence for the therapeutic effects of full-
doses, such experiences are often quite intense thus confer substantive participant risk. Popular
vernacular includes the term "bad trip", and, indeed, one study participant described a full-dose
experience as "the worst experience of her life" (Griffiths et al., 2011). In an online survey of the
worst “bad trips” experienced, 39% percent of participants rated their psychedelic experience
among the top five most challenging experiences of his/her lifetime (Carbonaro et al., 2016). At
the same time, Carbonaro et al. (2016) also found that despite the difficult experiences, 84% of
participants reported benefitting from the experience. Although research on LSD and psilocybin
suggest low risks for abuse or harmful effects (Amsterdam et al., 2011; Halpern and Pope, 1999;
Johnson et al., 2018), a small percentage of users are at risk of developing persisting perceptual
effects (Hallucinogen Persisting Perception Disorder; Martinotti et al., 2018) or risk being
hospitalized for acute intoxication, especially if mixed with alcohol (Hardaway et al., 2016).
While large population studies suggest that psychedelics are not usually associated with
detrimental mental health outcomes (Krebs & Johansen, 2013), microdosing may circumvent this
issue as anecdotal reports suggest numerous positive outcomes without the risks associated with
acute full-dose intoxication (Fadiman, 2011).
1.2 The Present Study
In this study we describe the psychological profile of the growing microdosing
community by making comparisons against a population of non-microdosers. We compared
groups of self-described microdosers (current and former microdosers) against controls (no
microdosing experience) across a variety of mental health and personality variables. These
include dysfunctional attitudes (de Graaf et al., 2009), wisdom (Glück et al., 2013), negative
emotionality and open-mindedness (Soto and John, 2016), and creativity (Silvia, 2011). This
study is part of a larger project that also reports on the demographics and psychiatric history of
microdosing users (Rosenbaum et al., 2018). A qualitative report examining subjective benefits
and drawbacks of microdosing is also in preparation (Anderson et al., 2018). We presently
address pre-registered hypotheses about the outcomes associated with microdosing experience on
validated scales.
2. Methods
2.1 Pre-Registered Hypotheses
Prior to data collection this study was pre-registered on the Open Science Framework
(OSF; We define "Microdosers" as those participants with experience
microdosing, whether current or former use. We pre-registered the following hypotheses:
Mental Health Vulnerability, Wisdom, and Personality
While the mechanisms driving psychedelic substances’ clinical efficacy are unclear,
several psychological constructs are likely involved. These include practical indicators of
flourishing, such as freedom from dysfunctional beliefs about oneself, other people, and the
world; wisdom; and personality traits, especially neuroticism and openness to experiences.
Psychedelic substances are purported to have profound effects on one’s understanding of
the self and world, leading to enhanced insight and personal growth (Domínguez-Clavé et al.,
2016; Dos Santos et al., 2016; Kometer et al., 2015; Strassman, 2016). As such, we hypothesized
that microdosers would have lower dysfunctional attitudes and higher wisdom than non-
microdosers. Furthermore, improved mood and reduced mental health concerns are commonly
reported outcomes of microdosing online (/r/microdosing subreddit, Reddit Inc, San Francisco,
CA, USA). For this reason, we hypothesized that microdosers would have lower negative
emotionality (depression, anxiety, and emotional volatility) than non-microdosers. Finally,
participants experiencing a single full dose of psilocybin showed a robust and sustained increase
in openness (MacLean et al., 2011); we therefore predicted that microdosers would also have
higher openness.
H1a: Microdosers will have lower dysfunctional attitude scores than non-microdosers.
H1b: Microdosers will have higher wisdom scores than non-microdosers.
H1c: Microdosers will have lower negative emotionality scores than non-microdosers.
H1d: Microdosers will have higher open-mindedness scores than non-microdosers.
The Broaden and Build theory (Fredrickson, 2004) proposes a link between positive
emotions and relaxed cognitive constraints as improved well-being may recruit personal
resources in the generation of creative ways of coping with challenges. Enhanced creativity is
one of the commonly reported outcomes of microdosing in media reports (Solon, 2016) and
online (/r/microdosing subreddit, Reddit Inc, San Francisco, CA, USA) and is often reported as a
benefit of full-dose psychedelics (Fadiman, 2011).
H2: Microdosers will have higher creativity scores than non-microdosers.
Importance of Benefits
Participants were asked to rate how important qualitative benefits of microdosing were to
them. We used this measure of subjective "importance of benefits” as a broad outcome of
participants' positive valuation of microdosing. Based on online anecdotal reports we predicted
that there would be a total-dose response curve such that microdosers would rate the importance
of benefits as quickly increasing to a plateau. Concerning dose scheduling, James Fadiman
(2011) proposed a dose-schedule such that microdosers consume their substance one day, then
refrain for two days, then dose again; we hypothesized that this schedule would show optimal
reported importance of benefits compared to alternate dose frequencies, perhaps due to
substance-tolerance (more frequent) or limited efficacy (less frequent).
Total Doses and Dose Frequency
H3a: A logarithmic relationship will exist between total lifetime microdoses and average
reported importance of benefits. Specifically, benefits are expected to be minimal with
minimal total doses, then increase, and subsequently stabilize at a plateau.
H3b: A quadratic relationship will exist between frequency of microdosing and average
reported importance of benefits. Specifically, maximum benefits are expected when
participants report frequency of microdoses at ~3 days between microdoses with reduced
benefits for shorter and longer frequencies.
More frequent and more intense positive experiences with a substance motivate future
use of that substance (de Wit and Phillips, 2012). As such, microdosers with a more extensive
history of full-dose psychedelic use may be especially motivated to try microdosing and may
evaluate benefits of microdosing more highly. This positivity bias may extend beyond
psychedelics as, more generally, substance use is associated with greater openness to experience
(Gunnarsson et al., 2008; Terracciano et al., 2008; Trull and Sher, 1994), which may include an
openness to try novel pharmacological interventions, such as microdosing.
Substance-Use History
H4a: Microdosers reporting at least one life-time use of a classic psychedelic (LSD,
psilocybin mushrooms, DMT, ayahuasca, mescaline) at full dose will report higher
average importance of benefits than microdosers that have not had a full dose.
H4b: Microdosers reporting greater variety of recreational substance use ("Polydrug user
experience index", see below) will report higher average importance of benefits than
microdosers with less recreational substance experience.
2.2 Deviations from Pre-Registration
A survey-flow error resulted in unintended data-collection on dose frequency and
importance (H3 and H4) from participants with no experience microdosing; this data has been
2.3 Participants
Participant were snowball-recruited via social media (e.g. Facebook, Twitter) and
recruited through posts on the online forum "reddit" (Reddit Inc, San Francisco, CA, USA): links
were posted under the username /u/oredna on the following subreddits: Microdosing, Nootropics,
Psychonaut, RationalPsychonaut, Tryptonaut, Drugs, LSD, shrooms, DMT, researchchemicals,
and SampleSize. Both participants with experience and participants without experience
microdosing psychedelics were recruited for this study. Participation was voluntary, and
participants were not remunerated. The survey was in English and internationally available.
Participants exited the online survey at different stages of completion; different analyses
therefore employ different numbers of participants. While 1390 respondents began the survey,
475 exited before responding, 3 requested that their responses be removed, and 3 responses were
removed for disingenuous responding, i.e. "trolling". In total 909 participants entered enough
data to be included in analyses, sorted into two categories: those with microdosing experience
(Microdosers: n = 594, 65%) and those without such experience (Non-microdosers: n = 315,
35%); full-dose experience with psychedelics was not considered for determining microdosing
status. Of these participants 29% were currently microdosing (current microdosers), 37% had
microdosed in the past but have since stopped (former microdosers), 30% were interested in
microdosing but had no prior experience, and 4% had no prior experience and reported not being
interested in microdosing. Participants from 29 countries responded to the survey (median age =
26, 82% males, 70% white). For a more comprehensive breakdown see the full epidemiological
report (Rosenbaum et al., 2018).
2.4 Design and Questionnaires
Following informed consent, participants completed online computer-based
questionnaires ( including questions pertaining to microdosing habits
(substance, frequency, dosage), substance use and mental health history, dispositional personality
variables (Dysfunctional Attitudes, Wisdom, Negative Emotionality, Open-Mindedness), and a
creativity task. Questions were displayed according to experience with microdosing, i.e.
individuals who reported never having microdosed were not shown questions related to a history
of microdosing (note survey flow error, 1.4.1 above). For uniformity, all scales were rated using
a continuous 0-100 slider-scale with nominal descriptors at 0 ("Disagree Strongly") and 100
("Agree Strongly") (Matejka et al., 2016). For brevity, methods reported here focus on variables
analyzed in this paper; a complete list of all questions is available on the OSF pre-registration.
2.4.1 Microdosing Substance
The majority of participants reported using LSD (65%) and/or Psilocybin (28%) for
microdosing; 16% reported using another substance. For a more comprehensive breakdown see
the full epidemiological report (Rosenbaum et al., 2018).
2.4.2 Mental Health Vulnerability
The DAS-A-17 is a short-version of the Dysfunctional Attitude Scale, a 40-item self-
report scale designed to measure the presence and intensity of dysfunctional beliefs (de Graaf et
al., 2009). Participants rate statements of beliefs (e.g. "If I fail at my work, then I am a failure as
a person.") on a 7-point Likert scale and the total score is the sum of the 17-items (range: 17
119) with higher scores indicating more dysfunctional attitudes (Weissman and Beck, 1978). The
DAS-A-17 includes a total-score and two subscales: "perfectionism/performance evaluation" (11
items) and "dependency" (6 items). Reliability for total score was excellent (α = 0.91) and good
for the subscales (perf: α = 0.87, dep: α = 0.85).
A Mental Health Index of psychological disorders was computed as a simple binary 0/1
based on the question, "Have you ever been diagnosed by a doctor or health care professional
(e.g., psychiatrist, psychologist) with any of the following diagnoses", which was followed by a
list of DSM-V diagnoses. Endorsing any diagnosis was coded as a "1", otherwise "None of the
above" was coded as "0". Comprehensive findings will be available in the epidemiological report
(Rosenbaum et al., 2018).
2.4.3 Wisdom
The Brief Wisdom Screening Scale (BWSS, (Glück et al., 2013) was developed by
selecting the 20 items that were most highly correlated with the common factor of "wisdom self-
report" across three leading wisdom self-report measures. Reliability was good (α = 0.86).
2.4.4 Personality
The Big Five Inventory 2 (BFI2, Soto and John, 2016) is an updated five-factor
personality measure using the commonly recognized five-factor model: Extraversion,
Agreeableness, Conscientiousness, Negative Emotionality (formerly “Neuroticism”), and Open-
Mindedness (formerly Openness to Experience). Our hypotheses were centered on two of these
subscales: Negative Emotionality and Open-Mindedness, thus only these factors were measured.
Reliability was good (Negative Emotionality α = 0.91, Open-Mindedness α = 0.79).
2.4.5 Creativity
The Unusual Uses Task is a task in which participants generate creative uses for mundane
objects (UUT; (Silvia, 2011). The UUT instructions emphasized the importance of original
responses, reading “Please try and think of the most unusual, creative, and uncommon uses you
can imagine” (Harrington, 1975). Participants were asked to give as many responses as they
could for each of two items (brick, knife), allotted one minute for each. During analysis,
responses were split into alphabetical lists to avoid within-participant biases. Responses were
rated by three independent research assistants using three dimensions: uncommon, clever, and
remote (Silvia et al., 2008). Dimension-scores across objects were averages to produce three
dimension-scores. Intraclass correlation coefficient was moderate for each dimension
(Uncommon: 68.25, Remote: 57.25, Clever: 59.75) and moderate for each object (brick = .61,
knife = .64).
2.4.6 Importance of Benefits
Participants rated qualitative benefits of microdosing in terms of personal, subjective
importance for three self-generated benefits. The average of these scores was then used as a
broad index of participants' subjective valuation of microdosing, analyzed in H3/4 in this study.
A taxonomy that organizes the participant-generated benefits has been generated using Grounded
Theory analysis and will be featured in an independent report (Anderson et al., 2018).
2.4.7 Microdosing Frequency
Microdosers reported the total number of lifetime microdoses taken (0 to 100). They also
reported dose scheduling, that is, the number of days spaced between each microdose (dose
every day to dose once every two months).
2.4.8 Substance-Use History
To test H4 concerning substance-use history, participants reported their experience with
full-dose psychedelics and with other substances. We developed a novel index: the "Polydrug
User Experience Index". This novel measure was computed as the sum of recreational
experiences across 13 classes of substance (e.g. Alcohol, Cannabis, MDMA, Stimulants, Opiates,
Dissociatives, etc.) accounting for recency of experience. Each class of substance was scored
according to the following metric: (a) used in past month: +4 points; (b) used in past year: +2
points; (c) used ever: +1 point; (d) never used: +0 points; (e) Prefer not to answer: +0 points.
Scores range from 052, with lower scores indicating less experience with recreational substance
2.4.9 Mood
A "Valence" score was computed using a mood-board ( as the count
of pleasant minus unpleasant items, as was an "Arousal" score for high-intensity minus low-
intensity moods.
3. Results
Table 1. Contrast between Microdosers and Non-Microdosers, means with standard deviations
and standardized effect-sizes.
27.23 (8.94)
26.36 (7.78)
4.72 (1.72)
4.78 (1.77)
0.50 (1.33)
0.51 (1.40)
Mood Valence
2.33 (4.40)
-0.16 (4.14)
Mood Intensity
-0.08 (2.42)
0.02 (2.40)
Dysfunctional Attitudes (DAS-17)3
40.62 (16.28)
49.30 (16.33)
Wisdom (BWSS)
66.68 (13.16)
60.05 (12.98)
Negative Emotionality (BFI-2)
41.53 (20.06)
48.16 (18.89)
Open-Mindedness (BFI-2)
76.43 (12.44)
73.33 (13.16)
1 Education was coded according to the International Standard Classification of Education (UNESCO
Institute for Statistics, 2011): ISCED level 0 = Early childhood education, 1 = Primary education, 2 =
Lower secondary education, 3 = Upper secondary education, 4 = Post-secondary non-tertiary education
Tertiary education, 5 = Short-cycle tertiary education, 6 = Bachelor’s or equivalent level, 7 = Master’s
or equivalent level, 8 = Doctoral or equivalent level
2 Socio-Economic Status (SES) was coded as: -3 = Non-working class (casual workers, pensioners, or
dependents); -2 = Working class (semi-skilled or unskilled manual workers); -1 = Skilled working class
(skilled manual workers); 0 = Lower-middle class (junior managerial, administrative, or professional); 1
= Middle class (intermediate managerial, administrative, or professional); 2 = Upper-middle class
(higher managerial, administrative, or professional); 3 = Upper class (royalty or immense heritable
3 DAS scores have been transformed to the original DAS-17 scale (17-119).
Table 2. Follow-up Analysis of Microdosers (Current versus Former), means with standard
deviations and standardized effect-sizes.
Effect size
d [95% CI]
28.89 (9.71)
25.93 (8.06)
0.33 [ 0.16 , 0.51 ]
4.83 (1.70)
4.64 (1.73)
0.11 [ -0.06 , 0.28 ]
0.48 (1.34)
0.52 (1.32)
-0.03 [ -0.2 , 0.14 ]
Mood Valence
2.93 (4.57)
1.86 (4.21)
0.24 [ 0.08 , 0.41 ]
Mood Intensity
0.10 (2.38)
-0.23 (2.45)
0.14 [ -0.03 , 0.3 ]
Dysfunctional Attitudes (DAS-17)
39.53 (14.58)
41.53 (17.56)
-0.12 [ -0.36 , 0.11 ]
Wisdom (BWSS)
66.09 (12.86)
67.18 (13.42)
-0.08 [ -0.32 , 0.15 ]
Negative Emotionality (BFI-2)
43.32 (19.98)
39.95 (20.07)
0.17 [ -0.06 , 0.4 ]
Open-Mindedness (BFI-2)
77.06 (11.91)
75.87 (12.91)
0.09 [ -0.13 , 0.32 ]
3.1 Pre-Registered Hypotheses and Planned Follow-up Analysis
3.1.1 Mental Health Vulnerability, Wisdom, and Personality
Mental Health Vulnerability. Microdosing predicted lower scores on Dysfunctional
Attitudes (b = -8.69, 95% CI [-12.48 -4.89], z(364) = -4.49, p < .001, r = -0.92), even when
controlling for a history of mental illness, which was also significant (b = 5.74, 95% CI [2.45
9.03], z(364) = 3.42, p < .001, r = 0.85) (Figure 2). Dysfunctional Attitudes were not related to
current versus former microdosing (b = 1.90, 95% CI [-1.91 5.71], p = 0.33), nor to type of
substance used (LSD vs Psilocybin: b = 0.56, 95% CI [-4.93 6.05], p = 0.842), nor to total
number of lifetime microdoses (b = -1.66, 95% CI [-3.47 0.15], p = 0.074).
Figure 2. Differences in dysfunctional attitudes between microdosers and non-microdosers
including breakdown by history of mental illness. The asterisk (*) indicates a significant main
effect of microdosing status such that microdosers showed lower dysfunctional attitudes than
non-microdosers (p < 0.001). Respondents with no history of mental illness (blue) also had lower
dysfunctional attitudes than those with a history of mental illness (orange, p < 0.001), though
microdosing status was a significant predictor even controlling for this potent covariate.
Wisdom. Microdosing predicted higher wisdom scores (b = 6.61, 95% CI [3.52 9.69],
z(367) = 4.19, p < .001, r = 0.88) when controlling for age and level of education, which were
not significant (age: b = -0.11, 95% CI [-0.26 0.04], p = 0.16, education: b = 0.40, 95% CI [-0.43
1.24], p = 0.35). No significant differences were found between current and former microdosers
(b = 1.09, 95% CI [-1.96 4.13], p = 0.48), nor type of substance used (b = 1.37, 95% CI [-2.83
5.57], p = .523), nor total lifetime number of microdoses (b = 0.62, 95% CI [-0.80 2.05], p =
Negative Emotionality. Microdosing predicted lower Negative Emotionality (b = -5.78,
95% CI [-10.13 -1.43], z(396) = -2.60, p = .009, r = -0.85), even after controlling for gender,
which was also a significant predictor (higher Negative Emotionality in females, b = 10.49, 95%
CI [5.33 15.65], z(396) = 3.99, p < .001, r = 0.95). Planned follow-up analysis tested the
difference between current and former microdosers and no significant difference existed between
the groups (b = -2.95, 95% CI [-7.47 1.58], p = 0.20), nor between substance used (b = -5.18,
95% CI [-11.50 1.15], p = .110), nor any effect of lifetime number of microdoses (b = -0.25, 95%
CI [-2.38 1.89], p = 0.82) on Negative Emotionality.
Open-Mindedness. Microdosing predicted greater Open-Mindedness (b = 3.24, 95% CI
[0.38 6.10], z(392) = 2.22, p = .027, r = 0.67), including when controlling for education, which
was not significant (b = 0.08, 95% CI [-0.65 0.81],p = 0.83). Again there were no significant
differences between current and former microdosers (b = -1.18, 95% CI [-4.00 1.64], p = 0.41),
nor type of substance used (b = 1.35, 95% CI [-2.61 5.31], p = .506), nor total lifetime number of
microdoses (b = 0.77, 95% CI [-0.55 2.09], p = 0.26).
3.1.2 Creativity
Microdosing predicted higher scores on all three creativity facets: on average, responses
made by microdosers were more clever (b = 0.57, SE = 0.13, z(423) = 4.25, p < .001, r = 0.15),
more uncommon (b = 0.50, SE = 0.15, z(427) = 3.42, p < .001, r = 0.14) and more remote (b =
0.74, SE = 0.16, z(425) = 4.49, p < .001, r = 0.20).
3.1.3 Importance of Benefits
Self-reported "importance of benefits” was intended to reflect participants' broad
valuation of microdosing. Counter to H3a/b, no significant differences were found in reported
importance of benefits when regressed on lifetime microdoses (b = 1.01, 95% CI [-0.81 2.82], p
= .277) nor frequency of microdosing regardless of explored linear and non-linear relationships
(raw: b = -0.07, 95% CI [-0.66 0.53], p = 0.83; squared: b = -0.0004, 95% CI [-0.01 0.01], p =
0.94; logarithmic: b = 1.21, 95% CI [-2.68 5.09],p = 0.54). Counter to H4a/b there were also no
significant difference in the importance of benefits between participants who had previous
experience with full-dose classic psychedelics and those who had no such experience (b = -4.09,
95% CI [-11.80 3.61], p = 0.30) nor based on the variety and recency of recreational substance
use (Polydrug User Experience Index: b = -0.006, 95% CI [-0.26 0.25], p = 0.96).
3.2 Exploratory Analysis
Exploratory comparison of mood measures (valence and intensity, Tables 1&2) by
Welch's t-test revealed that microdosers reported significantly more positive valence (M=2.33,
SD=4.40) than non-microdosers (M=-0.16, SD=4.14; difference: 2.49, 95% CI [1.91 3.07],
t(675) = 8.44, p < .001, r = 0.31). No differences were found for mood intensity (difference: -
0.11, 95% CI [-0.44 0.22] p = 0.53). For valence, current microdosers (M=2.93, SD=4.57) also
reported more positive valence than former microdosers (M=1.86, SD=4.21; difference: 1.07,
95% CI [0.35 1.79], t(533) = 2.92, p = .004, r = 0.13), but no difference in mood intensity
(difference: 0.33, 95% CI [-0.06 0.72], p = 0.10).
4. Discussion
This is the first preregistered report on microdosing psychedelics and is intended to
inform future lab-based clinical intervention studies. We investigated psychedelic microdosing in
online communities and tested pre-registered hypotheses (Anderson et al., 2017) concerning the
relationship between experience with microdosing and various mental health and personality
variables. Our results suggest a beneficial relationship wherein experience with microdosing is
associated with lower dysfunctional attitudes and negative emotionality and higher wisdom,
open-mindedness, and creativity. The most popular substances used to microdose were LSD and
psilocybin, and no significant differences based on substance were found on our quantitative
measures. The qualitative benefits and drawbacks collected in this survey may yet reveal
substance-based effects (Anderson et al., 2018). Hypotheses predicting perceived importance of
microdosing from dose-related practices were unsupported and optimal dose scheduling remains
an open question. Exploratory analyses revealed that microdosers, especially current
microdosers, had more positive emotional valence than non-microdosers, whereas emotional
intensity was not significantly different. Taken together, these findings suggest that randomized,
placebo-controlled clinical trials (RCTs) of microdosing are warranted to investigate the causal
efficacy of microdosing.
Consistent with our hypotheses, microdosing experience was associated with
meaningfully lower levels of dysfunctional attitudes. Individuals with higher dysfunctional
attitudes maintain a set of disadvantageous beliefs that increase vulnerability to stressors (Jarrett
et al., 2012) and high scores are associated with depression (Adler et al., 2015; de Graaf et al.,
2009). Also consistent with our hypotheses was the lower negative emotionality seen in
microdosers, though the estimated effect was less precise. Tendencies to experience negative
emotionality (e.g. anxiety, depression, emotional volatility) are a robust predictor of mental and
physical health problems (Lahey, 2009) thus reduced vulnerability is reflected in the lower
scores seen in microdosers. Exploratory analysis revealed that microdosers had more positive
emotional valence than non-microdosers, linking microdosing to better mood states. While
causation cannot be inferred from these results, significant differences were preserved even after
controlling for potent covariates, such as gender and history of mental illness, indicating a
potentially distinct contribution of microdosing on mental health vulnerability that warrants
further study.
Microdosers also had higher wisdom, which is a complex trait (BWSS, Glück et al.,
2013). As measured by the BWSS, wisdom is understood to reflect learning from one's mistakes,
considering multiple perspectives when facing a situation, being in tune with one's own emotions
and the emotions of others, and feeling a sense of connection and unity. Higher scores, as seen in
this sample of microdosers, may be associated with cognitive and emotional processing
differences including enhanced capacity for perspective taking, resilience in the face of the
vicissitudes of life, and increased feelings of engagement and connection. RCT research
addressing the relationship between wisdom and microdosing are warranted.
Greater open-mindedness was expected in microdosers compared to controls due to
previous studies noting increases in openness following a full-dose of psilocybin (MacLean,
Johnson, & Griffiths, 2011). These differences were supported, though this effect was relatively
weaker than the others. Still, given the findings from full-dose psychedelic studies, future clinical
intervention research should continue investigating any causal relationship between open-
mindedness and microdosing.
Microdosers were more creative when finding unusual uses for household items. This is
consistent with Fredrickson's (2004) Broaden and Build theory, which suggests a positive
relationship between creativity and positive affect, which was also seen in microdosers. Happier,
more creative people may be more likely to apply novel modes of thinking in their personal and
interpersonal challenges (Fredrickson, 2004). Our findings are also consistent with the anecdotal
reports that a relationship between microdosing, creativity, and mood exists, but RCTs, ideally
with multiple creativity measures, are required.
None of our hypotheses concerning the importance of microdosing benefits and
microdosing practices were supported. It is likely that this measure was not sensitive and specific
enough; planned analyses of qualitative benefits and drawbacks of microdosing will be explored
in a separate report (Anderson et al., 2018). It may be that microdosing frequency is truly
unrelated to the subjective valuation of microdosing, but this seems improbable. We suggest that
this research question is best addressed in RCT studies focused on specific benefits with
experimental manipulation of dose and schedule to determine optimal benefit-specific protocols.
Similarly, there is no evidence that outcomes are predicated on prior experience with substances,
whether full-dose psychedelics or with a variety of substances. More microdosers had experience
with full-doses (69%, n=412) then did not (31%, n=182) and many microdosers (and non-
microdosers) had experience with full-dose psychedelics within the month prior to completing
the survey. As full-dose psychedelics can have benefits lasting at least a month (Carhart-Harris et
al., 2017) this covariate should be formally modelled in future microdosing research designs,
which should aim to include both psychedelic-naïve and psychedelic-experienced participants.
5. Limitations and Future Directions
The sample is both a strength and a limitation of this study. This sample represents a true
community of microdosers with dozens of countries represented, however, countries in the
Anglo cultural cluster make up the majority of the sample (>70%) and participants were
predominantly middle-class, white, male, and heterosexual. Sampling from online communities,
including Reddit, could create a demographic bias thus we cannot suggest a definitive
epidemiological generalization. Despite this limitation, this sample does inform us about real
community practices in an otherwise unstudied population and reflects our sample of interest.
A second limitation of this study is its correlational nature. This cross-sectional design
contained no longitudinal component or experimental manipulation and cannot be used to infer
causal relationships. Our findings of group-differences do not infer that microdosing caused
these differences as some of the measured constructs may even promote an increased willingness
to explore microdosing, e.g. open-mindedness. Instead, these findings are intended as a
descriptive foundation upon which experimental and clinical studies of psychedelic microdosing
can be designed, exploring the directionality of relationships established in the present study.
To test causal hypotheses concerning microdosing effects, pre-registered randomized
placebo-control trials (RCTs) are needed. With random assignment to microdose or placebo it
would be possible to determine whether microdosing causally influences mental health and
personality. Following positive causal findings, mechanistic studies could then investigate the
observed efficacy in terms of physiological, psychological, and neurobiological changes.
Promisingly, microdosing may prove easier to administer, monitor, and placebo-control
in lab settings due to the absence of the intense perceptual shifts induced by full-doses.
Microdosing may thus be amenable to designs that could aid in mapping the neural mechanisms
behind psychedelic efficacy. Microdosing could also be explored as an adjunct to long-term
psychotherapy predicated on the longitudinal cultivation of resilience and insight, a new
paradigm that could compliment the acutely transformative model underlying high-dose
psychedelic psychotherapy (Rosenbaum et al., 2018).
6. Conclusion
This study provides initial, correlational evidence for mental health and personality
benefits associated with microdosing psychedelics. While anecdotal reports of microdosing
benefits have existed for some time (Fadiman, 2011), this study marks the first formal study of
the topic. Additionally, the use of a pre-registered study design sets a precedent for responsible
and replicable psychedelic microdosing research. To add depth to the current discussion, a full
epidemiological report (Rosenbaum et al., 2018) and a Grounded Theory analysis of qualitative
outcomes (Anderson et al., 2018) are forthcoming.
The results of the present study suggest that there is a significant relationship between
microdosing experience and measures of mental health and flourishing including lower
dysfunctional attitudes and negative emotionality, higher wisdom and open-mindedness, and
higher creativity and affect-valence. These findings are the initial evidence that warrants RCTs to
directly test safety and therapeutic efficacy. With almost 40,000 users subscribing to the
/r/microdosing subreddit and thousands more reading media reports on microdosing this growing
community continues to explore microdosing and its effects. It is our hope that scientific
reporting can help to clarify and inform the public about the nature of microdosing’s putative
effects and that this new paradigm helps shape future psychedelic research. We hope that
researchers will draw on our shared resources ( and pre-register studies of
their own so that psychedelic science will be built upon strong research practices. Insights from
these and other studies will form the backbone of future research into microdosing psychedelics
Conflict of interest statement
On behalf of all authors, the corresponding author states that there is no conflict of interest.
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... Second, in an open label study, Prochazkova et al. [21] found that microdosing led to increases in convergent and divergent thinking-common indicators of creativity. Third, a large cross sectional study found that microdosers reported reduced levels of negative attitudes and emotions, and increased wisdom, open-mindedness and creativity, relative to people who had never microdosed [22]. Fourth, the most scientifically rigorous study to date, was a double blind placebo controlled study by Yanakieva et al. [23]. ...
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The phenomenon of ‘microdosing’, that is, regular ingestion of very small quantities of psychedelic substances, has seen a rapid explosion of popularity in recent years. Individuals who microdose report minimal acute effects from these substances yet claim a range of long-term general health and wellbeing benefits. There have been no published empirical studies of microdosing and the current legal and bureaucratic climate makes direct empirical investigation of the effects of psychedelics difficult. In Study One we conducted a systematic, observational investigation of individuals who microdose. We tracked the experiences of 98 microdosing participants, who provided daily ratings of psychological functioning over a six week period. 63 of these additionally completed a battery of psychometric measures tapping mood, attention, wellbeing, mystical experiences, personality, creativity, and sense of agency, at baseline and at completion of the study. Analyses of daily ratings revealed a general increase in reported psychological functioning across all measures on dosing days but limited evidence of residual effects on following days. Analyses of pre and post study measures revealed reductions in reported levels of depression and stress; lower levels of distractibility; increased absorption; and increased neuroticism. To better understand these findings, in Study Two we investigated pre-existing beliefs and expectations about the effects of microdosing in a sample of 263 naïve and experienced microdosers, so as to gauge expectancy bias. All participants believed that microdosing would have large and wide-ranging benefits in contrast to the limited outcomes reported by actual microdosers. Notably, the effects believed most likely to change were unrelated to the observed pattern of reported outcomes. The current results suggest that dose controlled empirical research on the impacts of microdosing on mental health and attentional capabilities are needed.
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The Benefits and Drawbacks of Microdosing Psychedelics Microdosing psychedelics is the practice of taking very low doses of psychedelic substances (e.g. LSD, psilocybin). Psychedelic microdosing has recently been featured in numerous popular-media reports yet no scientific studies have been published on this topic. At present only anecdotes regarding the effects of microdosing are discussed and these have not been described in the scientific literature. To address these literature gaps we ran the first pre-registered scientific study on microdosing psychedelics by investigating the practices of online communities already engaging in this activity. This pre-registered online study collected 1034 benefits and 791 drawbacks drawn from 577 participants. These data were subjected to classic Grounded Theory analysis and a number of highly relevant conceptual groupings of benefits and drawbacks emerged. By discussing these groupings and suggesting psychometric measures intended to assess these outcomes this lecture will provide researchers with tangible suggestions for incorporating relevant measures into their psychedelic studies. We will also make recommendations that inform the non-academic community about the potential outcomes of microdosing with added focus on harm-reduction. This research informs both the individuals already microdosing and the scientific community intending to study microdosing and psychedelic outcomes in the future.
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Conclusions: (1) psilocybin has an abuse potential appropriate for CSA scheduling if approved as medicine; (2) psilocybin can provide therapeutic benefits that may support the development of an approvable New Drug Application (NDA) but further studies are required which this review describes; (3) adverse effects of medical psilocybin are relatively low and manageable when administered according to risk management approaches; and (4) although further study is required, this review suggests that placement in Schedule IV may be appropriate if a psilocybin-containing medicine is approved.
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Psilocybin with psychological support is showing promise as a treatment model in psychiatry but its therapeutic mechanisms are poorly understood. Here, cerebral blood flow (CBF) and blood oxygen-level dependent (BOLD) resting-state functional connectivity (RSFC) were measured with functional magnetic resonance imaging (fMRI) before and after treatment with psilocybin (serotonin agonist) for treatment-resistant depression (TRD). Quality pre and post treatment fMRI data were collected from 16 of 19 patients. Decreased depressive symptoms were observed in all 19 patients at 1-week post-treatment and 47% met criteria for response at 5 weeks. Whole-brain analyses revealed post-treatment decreases in CBF in the temporal cortex, including the amygdala. Decreased amygdala CBF correlated with reduced depressive symptoms. Focusing on a priori selected circuitry for RSFC analyses, increased RSFC was observed within the default-mode network (DMN) post-treatment. Increased ventromedial prefrontal cortex-bilateral inferior lateral parietal cortex RSFC was predictive of treatment response at 5-weeks, as was decreased parahippocampal-prefrontal cortex RSFC. These data fill an important knowledge gap regarding the post-treatment brain effects of psilocybin, and are the first in depressed patients. The post-treatment brain changes are different to previously observed acute effects of psilocybin and other ‘psychedelics’ yet were related to clinical outcomes. A ‘reset’ therapeutic mechanism is proposed.
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Conference Paper
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Sliders and Visual Analogue Scales (VASs) are input mechanisms which allow users to specify a value within a predefined range. At a minimum, sliders and VASs typically consist of a line with the extreme values labeled. Additional decorations such as labels and tick marks can be added to give information about the gradations along the scale and allow for more precise and repeatable selections. There is a rich history of research about the effect of labelling in discrete scales (i.e., Likert scales), however the effect of decorations on continuous scales has not been rigorously explored. In this paper we perform a 2,000 user, 250,000 trial online experiment to study the effects of slider appearance, and find that decorations along the slider considerably bias the distribution of responses received. Using two separate experimental tasks, the trade-offs between bias, accuracy, and speed-of-use are explored and design recommendations for optimal slider implementations are proposed.
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To date, pharmacological treatments for mood and anxiety disorders and for drug dependence show limited efficacy, leaving a large number of patients suffering severe and persistent symptoms. Preliminary studies in animals and humans suggest that ayahuasca, psilocybin and lysergic acid diethylamide (LSD) may have antidepressive, anxiolytic, and antiaddictive properties. Thus, we conducted a systematic review of clinical trials published from 1990 until 2015, assessing these therapeutic properties. Electronic searches were performed using the PubMed, LILACS, and SciELO databases. Only clinical trials published in peer-reviewed journals were included. Of these, 151 studies were identified, of which six met the established criteria. Reviewed studies suggest beneficial effects for treatment-resistant depression, anxiety and depression associated with life-threatening diseases, and tobacco and alcohol dependence. All drugs were well tolerated. In conclusion, ayahuasca, psilocybin and LSD may be useful pharmacological tools for the treatment of drug dependence, and anxiety and mood disorders, especially in treatment-resistant patients. These drugs may also be useful pharmacological tools to understand psychiatric disorders and to develop new therapeutic agents. However, all studies reviewed had small sample sizes, and half of them were open-label, proof-of-concept studies. Randomized, double-blind, placebo-controlled studies with more patients are needed to replicate these preliminary findings.
Rationale Microdosing psychedelics – the practice of consuming small, sub-hallucinogenic doses of substances such as LSD or psilocybin – is gaining attention in popular media but remains poorly characterized. Contemporary studies of psychedelic microdosing have yet to report the basic psychiatric descriptors of psychedelic microdosers. Objectives To examine the practices and demographics of a population of psychedelic microdosers – including their psychiatric diagnoses, prescription medications, and recreational substance use patterns – to develop a foundation on which to conduct future clinical research. Methods Participants ( n = 909; M age = 26.9, SD = 8.6; male = 83.2%; White/European = 79.1%) recruited primarily from the online forum Reddit completed an anonymous online survey. Respondents who reported using LSD, psilocybin, or both for microdosing were grouped and compared with non-microdosing respondents using exploratory odds ratio testing on demographic variables, rates of psychiatric diagnoses, and past-year recreational substance use. Results Of microdosers, most reported using LSD (59.3%; M dose = 13 mcg, or 11.3% of one tab) or psilocybin (25.9%; M dose = 0.3 g of dried psilocybin mushrooms) on a one-day-on, two-days-off schedule. Compared with non-microdosers, microdosers were significantly less likely to report a history of substance use disorders (SUDs; OR = 0.17 (95% CI: 0.05–0.56)) or anxiety disorders (OR = 0.61 (95% CI: 0.41–0.91)). Microdosers were also more likely to report recent recreational substance use compared with non-microdosers (OR = 5.2 (95% CI: 2.7–10.8)). Conclusions Well-designed randomized controlled trials are needed to evaluate the safety and tolerability of this practice in clinical populations and to test claims about potential benefits.
Use of hallucinogenic substances as a public health concern has increased over the past decade. Among adolescents, there are increasing emergency department presentations for intoxication with these drugs, contrary to decreasing reported use of classical hallucinogens such as LSD. Academic and governmental groups have monitored use of hallucinogens, highlighting a notable change in perceptions about use among adolescents thought to contribute to these trends. Special populations and religious groups, though, have been granted governmental permission to use hallucinogens for their cultural practices. Novel designer hallucinogens have gained popularity and may have serious medical and psychological side effects from use.